Sheet metal subcontractor, Keller Blechtechnik in Endingen, southern Germany, has increased productivity by more than 25 per cent thanks to ongoing investment in automated storage, retrieval and handling of material. At the same time, material availability has improved and scrap has been drastically reduced.
The firm, which employs over 40 people, was started as a forge and blacksmith's workshop in 1901 by the great-grandfather of the current managing partner, Harald Keller. He joined the company in 2001 and has overseen a rapid progression towards the supply of sheet metal parts and assemblies to customers in such diverse industries as automotive, food production, medical, pharmaceutical, agricultural, solar and general mechanical engineering.
The extensive customer base continually presents challenges due to the wide range of different materials that need to be supplied. Previously, they were stored at several different locations, which made planning, transport and handling time-consuming. Today the situation is very different. With the help of Kasto, Keller created a made-to-measure storage and material flow solution that he designed as the final project of his technician's training course.
The automated sheet metal storage and loading system fitted to the laser cutting machine is supplied directly with material from a Kasto Unitower B 3.0 computer-controlled sheet metal storage system, which has 89 pallet storage locations.
The pallets hold 3,000 x 1,500 mm sheets and can accommodate a stack 90 mm high of different sheet types, mainly steel, stainless steel and aluminium in thicknesses from 0.5 mm to 20 mm. Each location has a load capacity of 3 tonnes, so around 270 tonnes of sheet metal are available for immediate delivery.
The storage system offers high availability, so the company can react quickly to customer needs and priorities. To transfer system pallets to and from storage and to supply sheets directly to the loading system of the laser cutting cell, the system has one station with a transverse carriage and one with a longitudinal carriage. To allow unpacked sheet to be loaded and unloaded by forklift truck or crane, the transverse carriage is equipped with a hydraulic piston lifter.
The longitudinal carriage has a drop-off position for transfer of system pallets to and from storage and the return of pallets that are no longer needed during laser cutting. Both stations and carriages have an optical contour monitor to ensure safety in any pallet loading status and prevent malfunctions.
The operating gantry crane is responsible for pallet and sheet handling. It operates at a maximum speed of 22 m/min in the vertical direction, while pallet push/pull speed is 20 m/min. The Kasto EasyControl can be operated automatically or manually and handles order management for the complete storage system. There is also an interface to the laser cutting machine’s loading system to ensure smooth material transfer.
Martin Stöckle, sales team leader at Kasto, describes the ingenious solution installed at Keller Blechtechnik: "By using the standard versions of the Unitower B 3.0 sheet storage tower and adapting the arrangement of the transverse and longitudinal stations, we were able to design a very compact system.
“The space available was limited due to the layout of the laser cutting cell and other equipment. So we suggested installing the tower store behind an existing wall to transport the pallets to the loading system area by the shortest possible route."
This minimises delivery times, so the laser cutting machine can be operated almost continuously during the 1.5 manned shifts and unattended for the remainder of the 24 hours. Overall, a significant increase in productivity of around 25 per cent has been achieved compared with previous material storage practices. In addition, the ability to keep track of the material inventory has enabled the company to optimise its stock levels and reduce scrap.
Harald Keller concluded: "As well as increasing productivity by a quarter, the risk of material damage caused by frequent handling and transportation has been minimised. Additionally, working conditions for our staff are safer and more convenient.
“We have improved the utilisation of the laser cutting system thanks to shorter idle times and have eliminated transport from external storage locations and hence the need for weather protection.
“We now have a compact, cost-effective, 3D storage solution for a wider range of materials and therefore better availability to respond quickly to customer requirements.”